summaryrefslogtreecommitdiff
path: root/arch/arm/mach-exynos/hotplug.c
diff options
context:
space:
mode:
authorYuval Adam <_@yuv.al>2017-08-30 08:25:59 +0000
committerYuval Adam <_@yuv.al>2017-08-30 08:25:59 +0000
commit8e4bff4cab0ddac6060645b0715210484d02ff40 (patch)
tree3a5c3024371a04692a3a6d9974d001cdff8ebf84 /arch/arm/mach-exynos/hotplug.c
Initial file dump from open source releaseHEADmaster
Diffstat (limited to 'arch/arm/mach-exynos/hotplug.c')
-rw-r--r--arch/arm/mach-exynos/hotplug.c159
1 files changed, 159 insertions, 0 deletions
diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c
new file mode 100644
index 00000000..af90cfa2
--- /dev/null
+++ b/arch/arm/mach-exynos/hotplug.c
@@ -0,0 +1,159 @@
+/* linux arch/arm/mach-exynos4/hotplug.c
+ *
+ * Cloned from linux/arch/arm/mach-realview/hotplug.c
+ *
+ * Copyright (C) 2002 ARM Ltd.
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+#include <linux/io.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cp15.h>
+#include <asm/smp_plat.h>
+
+#include <mach/regs-pmu.h>
+#include <plat/cpu.h>
+
+#include "common.h"
+
+static inline void cpu_enter_lowpower_a9(void)
+{
+ unsigned int v;
+
+ asm volatile(
+ " mcr p15, 0, %1, c7, c5, 0\n"
+ " mcr p15, 0, %1, c7, c10, 4\n"
+ /*
+ * Turn off coherency
+ */
+ " mrc p15, 0, %0, c1, c0, 1\n"
+ " bic %0, %0, %3\n"
+ " mcr p15, 0, %0, c1, c0, 1\n"
+ " mrc p15, 0, %0, c1, c0, 0\n"
+ " bic %0, %0, %2\n"
+ " mcr p15, 0, %0, c1, c0, 0\n"
+ : "=&r" (v)
+ : "r" (0), "Ir" (CR_C), "Ir" (0x40)
+ : "cc");
+}
+
+static inline void cpu_enter_lowpower_a15(void)
+{
+ unsigned int v;
+
+ asm volatile(
+ " mrc p15, 0, %0, c1, c0, 0\n"
+ " bic %0, %0, %1\n"
+ " mcr p15, 0, %0, c1, c0, 0\n"
+ : "=&r" (v)
+ : "Ir" (CR_C)
+ : "cc");
+
+ flush_cache_louis();
+
+ asm volatile(
+ /*
+ * Turn off coherency
+ */
+ " mrc p15, 0, %0, c1, c0, 1\n"
+ " bic %0, %0, %1\n"
+ " mcr p15, 0, %0, c1, c0, 1\n"
+ : "=&r" (v)
+ : "Ir" (0x40)
+ : "cc");
+
+ isb();
+ dsb();
+}
+
+static inline void cpu_leave_lowpower(void)
+{
+ unsigned int v;
+
+ asm volatile(
+ "mrc p15, 0, %0, c1, c0, 0\n"
+ " orr %0, %0, %1\n"
+ " mcr p15, 0, %0, c1, c0, 0\n"
+ " mrc p15, 0, %0, c1, c0, 1\n"
+ " orr %0, %0, %2\n"
+ " mcr p15, 0, %0, c1, c0, 1\n"
+ : "=&r" (v)
+ : "Ir" (CR_C), "Ir" (0x40)
+ : "cc");
+}
+
+static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
+{
+ for (;;) {
+
+ /* make cpu1 to be turned off at next WFI command */
+ if (cpu == 1)
+ __raw_writel(0, S5P_ARM_CORE1_CONFIGURATION);
+
+ /*
+ * here's the WFI
+ */
+ asm(".word 0xe320f003\n"
+ :
+ :
+ : "memory", "cc");
+
+ if (pen_release == cpu_logical_map(cpu)) {
+ /*
+ * OK, proper wakeup, we're done
+ */
+ break;
+ }
+
+ /*
+ * Getting here, means that we have come out of WFI without
+ * having been woken up - this shouldn't happen
+ *
+ * Just note it happening - when we're woken, we can report
+ * its occurrence.
+ */
+ (*spurious)++;
+ }
+}
+
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ * Called with IRQs disabled
+ */
+void __ref exynos_cpu_die(unsigned int cpu)
+{
+ int spurious = 0;
+ int primary_part = 0;
+
+ /*
+ * we're ready for shutdown now, so do it.
+ * Exynos4 is A9 based while Exynos5 is A15; check the CPU part
+ * number by reading the Main ID register and then perform the
+ * appropriate sequence for entering low power.
+ */
+ asm("mrc p15, 0, %0, c0, c0, 0" : "=r"(primary_part) : : "cc");
+ if ((primary_part & 0xfff0) == 0xc0f0)
+ cpu_enter_lowpower_a15();
+ else
+ cpu_enter_lowpower_a9();
+
+ platform_do_lowpower(cpu, &spurious);
+
+ /*
+ * bring this CPU back into the world of cache
+ * coherency, and then restore interrupts
+ */
+ cpu_leave_lowpower();
+
+ if (spurious)
+ pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
+}